1. Field of the Invention
The present invention relates to a radio-frequency signal transceiver device capable of enhancing transmission and reception performance, and more particularly, a radio-frequency signal transceiver device capable of increasing signal power by receiving and transmitting radio-frequency signals without passing through filters.
2. Description of the Prior Art
As radio-frequency communications technology progresses, mobile phones have changed communication ways. Using a mobile phone, a user can exchange information with a destination anytime and anywhere, so that the user can call out for rescue in emergency. In the prior art, transmission and reception efficiencies of the mobile phone are highly related to distance, topography, buildings, etc. between the mobile phone and a nearest base station. Therefore, if the user goes deep into a mountain or other pathless places, the mobile phone may lose efficacy due to weak signal power. In this case, once the user suffers emergencies, such as landslide and robbery, the user cannot contact with lifesavers, and may loss the chance of being rescued.
Solutions of the above-mentioned problem are increasing base stations or improving the transmission and reception efficiencies of the mobile phone. The former one may increase cost of a system, while the latter one may cause the mobile phone failing in electromagnetic authentications or interfering with electronic devices. For example, FIG. 1 illustrates a schematic diagram of a transceiver device 10. The transceiver device 10 can be applied to a mobile communications device, such as mobile phones, personal digital assistants (PDA), etc. The transceiver device 10 includes an antenna 100, a transceiver switch module 102, a surface wave filter 104, a low noise amplifier 106, a frequency down-converter 108, a power amplifier 110, a frequency up-converter 112, and a signal processing module 114. The transceiver switch module 102 includes a switch 115, and filters 116 and 118. When the transceiver device 10 performs receiving, the switch 115 switches the antenna 100 to couple to the filter 116 according to a control signal Vc. Signals received from the antenna 100 pass through the filter 116 and the surface wave filter 104 for filtering noise, and the low noise amplifier 106 amplifies the filtered signals. Then, the frequency down-converter 108 converts frequencies of signals outputted from the low noise amplifier 106 into a range of baseband frequencies for the signal processing module 114 and transmits the signals such as sounds, messages, or images to the signal processing module 114. On the other hand, when the transceiver device 10 performs transmitting, the antenna 100 is switched to couple to the filter 118. The baseband signals outputted from the signal processing module 114 are converted to a frequency range of radio frequencies by the frequency up-converter 112. The power amplifier 110 amplifies the power of the signals, and the filter 118 filters noise of the amplified signals for preventing from interfering with other electronic devices. Then, the signals are transmitted into the air through the antenna 100.
Therefore, if the transmission and reception performance of the transceiver device 10 has to be enhanced, the transmission performance can be enhanced by increasing the gain of the power amplifier 110, but the only way to enhance the reception performance is to reduce power loss of the surface wave filter 104 and the transceiver switch module 102 due to physical limitations. However, increasing the gain of the power amplifier 110 will cause the mobile phone not only interfering with other electronic devices, but also failing in electromagnetic authentications.